The physarum polycephalum, a kind of slime mold, is a single-celled amoeboid organism [1]}. In 2000, Nakagaki et al. [2]} observed that the amoeboid organism would gradually change its shape to improve its efficiency of foraging, which leads to the result that its body would only cover the shortest path in the mazes after some time. The maze-solving ability of the slime mold was then considered as a kind of primitive intelligence [3]}. It is believed that the maze-solving mechanism which is also the path-finding mechanism was related to the contraction waves in the organism [4]}. The contraction waves influence the thickness of the tube, resulting in a positive mechanism. If the flow through a certain tube persists or increases for a certain period, the tube will become thicker; otherwise, the tube will contract [5]}.
